Roll handling equipment which is intended to grip the cores of rolls of material for the purpose of transporting the rolls has the advantage of not contacting the sides or ends of the rolls and therefore being less apt to damage the material wound upon the rolls. The strength and dependability of the core gripper dictates the size and weight of rolls that can be handled by the gripper. The mechanical strength of the core gripper is therefore the principle factor which limits the capacity of a core gripper.
In use, the core gripper is inserted into the core of a roll of material. The core gripper is then expanded inside the core so as to mechanically imbed into the core material and/or frictionally engage the core material. Rolls are frequently stored and lifted with the axis of the core vertical and therefore the strength of the engagement between the core gripper and the inside of the core is all that is carrying the weight of the roll at that time. When the roll is being held so that its axis is in the horizontal position, the core gripper is functioning in part as a cantilevered beam.
The problem faced by those wishing to increase the capacity and improve the performance of core grippers of this type is; one of providing the mechanical strength required for the several gripping and transporting requirements of the core gripper and doing it inside the small diameter permitted by the inside of roll cores.